Highways and highway construction techniques are generally known and are based on well-known practices. The state-of-the-art in road building technology, in fact, has not changed much over the centuries. Indeed, roads have not changed in any significant degree since old foot paths gradually expanded to support horse-and-buggy traffic, then motor cars and then became today's super-highways.
In contrast, the surfaces of roadways have improved somewhat. Roads now support much larger vehicles, at greater speeds, and in greater numbers.
To a significant degree, advances in roadway construction technology have come with the development of large earth moving machines, capable of excavating and moving several cubic yards of dirt and rocks in a single step, digging trenches to depths previously unthinkable, while other machines could fill and compact successive layers of aggregate into those trenches.
Sophisticated "mobile factories" can put down thin layers of asphalt consistently, mile after mile, over compacted aggregates. Alternatively, mobile cement mixers coupled to spreading and leveling equipment have been used to lay down relatively thick road surfaces of reinforced concrete. Often asphalt is added as a cushioning layer over the reinforced concrete.
Basic road building techniques and designs have not changed. Machines just do the work with greater efficiency and speed.
The whole process starts over in a few months as wear and tear, faulty (and sometimes shoddy) construction techniques, poor materials and weather extremes affect the integrity and driveability of the highway system. The US Interstate Highway system, built at costs approaching (and exceeding) $1 million per mile, is in a state of disrepair. Annual rebuilding of Interstate Highways is commonplace. The infrastructure is crumbling in every state of the union. Existing road surfaces have proven incapable of providing the load carrying capacities and speeds required by interstate commerce today. Cost estimates to rebuild America's infrastructure (e.g., highways and bridges, etc.) range from a hundred billion to as high as a trillion dollars. The annual cost of infrastructure maintenance, just in the United States, is in the billions.
In frostbelt countries, temperature differences between winter and summer affects the life of road surfaces. Frost heaves, and the use of snow plows and snow chains, cause damage to road surfaces. Pot holes and cracks in the roadway result from repeated melting and freezing of the roadway. Heavy truck traffic shortens the expected life span of roadways. Trucks exceeding weight and speed limits further exacerbate the problem.
In equatorial counties, extremes of heat and rain reduce life expectancy of road surfaces. High temperatures buckle roadways and damage asphalt. Traffic on heat softened asphalt results in permanent ruts. Water logged roadways often suffer surface damage, erosion, and catastrophic settling.
Insufficient funding, poor construction techniques, inadequate quality controls and inspections, inappropriate equipment and materials, compound rapid road surface deterioration problems in the U.S. and many other countries.
What is needed is a construction method that can accommodate today's high speeds and heavy traffic and is applicable to all climates and all countries. The highway produced by such methods should be easy to build and should adhere to measurable and enforceable construction standards, using materials that are readily available. It must advance the state-of-the-art in roadbuilding technology. It should be easy to build and re-build. It should be easy to maintain.